1. Field of the Invention
This invention relates to a reliable and portable combination lock and alarm having a flexible locking cable and alarm circuit by which to reduce the chance of theft and unauthorized displacement of protected property by causing an audible alarm signal to be sounded in the event that the cable is severed or the lock vandalized.
2. Background Art
Lock and alarm systems are known by which to prevent the theft and unauthorized use or displacement of valuable property, such as a bicycle, motorcycle, suitcase, and the like. Such conventional lock and alarm systems are also known to include a flexible cable having a fixed end connected to the lock and a free end surrounding an immovable object (e.g. a tree or a post) and detachably connected to the lock. In the event that the cable is cut in an effort to remove the protected property, an audible alarm is sounded to warn the property owner of an impending theft. Examples of known lock and alarm systems which include a locking cable to prevent the theft of protected property are available by referring to one or more of the following U.S. Pat. Nos.:
3,755,778, Aug. 28, 1973 PA0 3,772,645, Nov. 13, 1973 PA0 3,781,861, Dec. 25, 1973 PA0 3,824,540, July 16, 1974 PA0 3,824,541, July 16, 1974 PA0 3,914,756, Oct. 21, 1975 PA0 4,006,452, Feb. 1, 1977 PA0 4,057,986, Nov. 15, 1977 PA0 4,151,506, Apr. 24, 1979 PA0 4,340,007, July 20, 1982 PA0 4,663,611, May 5, 1987 PA0 4,776,188, Oct. 11, 1988
However, the above-identified systems have inherent limitations which might permit a thief to disable the lock and/or alarm and remove the protected property without sounding an alarm signal. That is to say, while some systems activate the alarm in the event that the locking cable is cut, it is still possible to jump the cable with a shunt wire in an effort to mask the fact that the locking cable has been severed. Moreover, the lock housing may be vandalized or cut in an effort to gain access to and remove the battery or disarm the alarm circuit. In either event, the known lock and alarm systems may be relatively easily overcome with the consequence of having one's valuable property stolen.
It would therefor be desirable to have available a more reliable combination lock and alarm system which would reduce the chance of theft of protected property by sounding an alarm warning signal should either the locking cable or the lock housing be cut or vandalized.